1,720,997 research outputs found
Model Building and Phenomenology in Grand Unified Theories
Get PDFThe Standard Model (SM) of particle physics is known to suffer from several flaws, and the upcoming generation of experiments may shed some light onto their solution. Whether there is evidence of new physics or not, theories Beyond the SM (BSM) must be able to accommodate and explain the coming data. The lack of signs of BSM physics so far, calls for a exhaustive exploration beyond the minimal models, in particular Grand Unified theories, for they are able to solve some of the issues of the SM and can make testable predictions. Therefore, we attempt to develop a framework to build Grand Unified models, capable of generating and analysing general non-minimal models. In order to do so, first we create a computational tool to handle the group theoretical component, calculating properties of Lie Groups and their representations. Among them, those of interest to the model building process are the calculation of breaking chains from a group to a subgroup, the decomposition of representations of a group into those of a subgroup and the construction of group invariants. Using some of the capabilities of the group tool, and starting with a set of representations and a breaking chain, we generate all the conceivable models, classifying them to satisfy conditions such as anomaly cancellation and symmetry breaking. We then move on to study the unification of gauge couplings on the models and its consequences on the scale of unification and the scale of supersymmetry breaking, to later constrain them to match phenomenological observables, such as proton decay or current collider searches. We conclude by focusing the analysis on two specific models, a minimal supersymmetric SO(10) model, with some interesting predictions for future colliders, and a flipped SU(5)xU(1) model, which serves as the triggering mechanism for the end of the inflationary epoch in the early universe
Neutrinos and collider physics
Get PDFModels of neutrino mass generation constitute well motivated scenarios of Beyond-the-Standard-Model physics. The interplay between high energy collider physics and low energy searches provides us with an effective approach to rule out, constrain and pinpoint such models. In this report, we give a brief overview of examples where collider searches at the LHC can help determine the mechanism of light neutrino mass generation and potentially falsify baryogenesis mechanisms
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Statistical analysis of beta decays and the effective value of g(A) in the proton-neutron quasiparticle random-phase approximation framework
Get PDFWe perform a Markov chain Monte Carlo (MCMC) statistical analysis of a number of measured ground-state-to-ground-state single β+/electron-capture and β− decays in the nuclear mass range of A=62–142. The corresponding experimental comparative half-lives (logft values) are compared with the theoretical ones obtained by the use of the proton-neutron quasiparticle random-phase approximation (pnQRPA) with G-matrix-based effective interactions. The MCMC analysis is performed separately for 47 isobaric triplets and 28 more extended isobaric chains of nuclei to extract values and uncertainties for the effective axial-vector coupling constant gA in nuclear-structure calculations performed in the pnQRPA framework. As far as available, measured half-lives for two-neutrino ββ− decays occurring in the studied isobaric chains are analyzed as well
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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